/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hbase.client;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.util.ReflectionUtils;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Factory to create an {@link RpcRetryingCaller}
 */
@InterfaceAudience.Private
public class RpcRetryingCallerFactory {

    /**
     * Configuration key for a custom {@link RpcRetryingCaller}
     */
    public static final String CUSTOM_CALLER_CONF_KEY = "hbase.rpc.callerfactory.class";
    private static final Logger LOG = LoggerFactory.getLogger(RpcRetryingCallerFactory.class);
    protected final Configuration conf;
    private final long pause;

    // pause for CallQueueTooBigException, if specified
    private final long pauseForCQTBE;
    private final int retries;
    private final int rpcTimeout;
    private final RetryingCallerInterceptor interceptor;
    private final int startLogErrorsCnt;

    /* These below data members are UNUSED!!!*/
    private final boolean enableBackPressure;
    private ServerStatisticTracker stats;

    public RpcRetryingCallerFactory(Configuration conf) {

        /********
         * TODO_MA 马中华 https://blog.csdn.net/zhongqi2513
         *   注释： interpretor 默认实现： NoOpRetryableCallerInterceptor
         */
        this(conf, RetryingCallerInterceptorFactory.NO_OP_INTERCEPTOR);
    }

    public RpcRetryingCallerFactory(Configuration conf, RetryingCallerInterceptor interceptor) {
        this.conf = conf;
        pause = conf.getLong(HConstants.HBASE_CLIENT_PAUSE, HConstants.DEFAULT_HBASE_CLIENT_PAUSE);
        long configuredPauseForCQTBE = conf.getLong(HConstants.HBASE_CLIENT_PAUSE_FOR_CQTBE, pause);
        if(configuredPauseForCQTBE < pause) {
            LOG.warn(
                    "The " + HConstants.HBASE_CLIENT_PAUSE_FOR_CQTBE + " setting: " + configuredPauseForCQTBE + " is smaller than " + HConstants.HBASE_CLIENT_PAUSE + ", will use " + pause + " instead.");
            this.pauseForCQTBE = pause;
        } else {
            this.pauseForCQTBE = configuredPauseForCQTBE;
        }
        retries = conf.getInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, HConstants.DEFAULT_HBASE_CLIENT_RETRIES_NUMBER);

        /********
         * TODO_MA 马中华 https://blog.csdn.net/zhongqi2513
         *   注释：5次
         */
        startLogErrorsCnt = conf.getInt(AsyncProcess.START_LOG_ERRORS_AFTER_COUNT_KEY, AsyncProcess.DEFAULT_START_LOG_ERRORS_AFTER_COUNT);
        this.interceptor = interceptor;
        enableBackPressure = conf.getBoolean(HConstants.ENABLE_CLIENT_BACKPRESSURE, HConstants.DEFAULT_ENABLE_CLIENT_BACKPRESSURE);
        rpcTimeout = conf.getInt(HConstants.HBASE_RPC_TIMEOUT_KEY, HConstants.DEFAULT_HBASE_RPC_TIMEOUT);
    }

    /**
     * Set the tracker that should be used for tracking statistics about the server
     */
    public void setStatisticTracker(ServerStatisticTracker statisticTracker) {
        this.stats = statisticTracker;
    }

    /**
     * Create a new RetryingCaller with specific rpc timeout.
     */
    public <T> RpcRetryingCaller<T> newCaller(int rpcTimeout) {

        /********
         * TODO_MA 马中华 https://blog.csdn.net/zhongqi2513
         *   注释： 看清楚实现类
         */
        // We store the values in the factory instance. This way, constructing new objects
        //  is cheap as it does not require parsing a complex structure.
        RpcRetryingCaller<T> caller = new RpcRetryingCallerImpl<>(pause, pauseForCQTBE, retries, interceptor, startLogErrorsCnt, rpcTimeout);
        return caller;
    }

    /**
     * Create a new RetryingCaller with configured rpc timeout.
     */
    public <T> RpcRetryingCaller<T> newCaller() {
        // We store the values in the factory instance. This way, constructing new objects
        //  is cheap as it does not require parsing a complex structure.
        RpcRetryingCaller<T> caller = new RpcRetryingCallerImpl<>(pause, pauseForCQTBE, retries, interceptor, startLogErrorsCnt, rpcTimeout);
        return caller;
    }

    public static RpcRetryingCallerFactory instantiate(Configuration configuration) {
        return instantiate(configuration, RetryingCallerInterceptorFactory.NO_OP_INTERCEPTOR, null);
    }

    public static RpcRetryingCallerFactory instantiate(Configuration configuration, ServerStatisticTracker stats) {
        return instantiate(configuration, RetryingCallerInterceptorFactory.NO_OP_INTERCEPTOR, stats);
    }

    public static RpcRetryingCallerFactory instantiate(Configuration configuration, RetryingCallerInterceptor interceptor,
            ServerStatisticTracker stats) {
        String clazzName = RpcRetryingCallerFactory.class.getName();
        String rpcCallerFactoryClazz = configuration.get(RpcRetryingCallerFactory.CUSTOM_CALLER_CONF_KEY, clazzName);
        RpcRetryingCallerFactory factory;
        if(rpcCallerFactoryClazz.equals(clazzName)) {
            factory = new RpcRetryingCallerFactory(configuration, interceptor);
        } else {
            factory = ReflectionUtils.instantiateWithCustomCtor(rpcCallerFactoryClazz, new Class[]{Configuration.class}, new Object[]{configuration});
        }

        // setting for backwards compat with existing caller factories, rather than in the ctor
        factory.setStatisticTracker(stats);
        return factory;
    }
}
